1. Field of the Invention
The present invention relates to a lens frame structure which moves a lens frame forwards and backwards.
2. Description of the Related Art
In a lens barrel in which a lens frame capable of moving forwards and backwards is incorporated, it is demanded that, even if impact is applied to a camera owing to drop or the like, the incorporated lens frame should move so that a lens is protected from breakage.
An actuator unit disclosed in Japanese Patent Application Laid-Open No. 2005-292514 is a unit which is applicable to an optical device of a small-sized camera. This actuator unit has a lens frame structure which moves the lens frame forwards and backwards along a guide shaft. In a case where an impact force is applied to this actuator unit in an optical axis direction, the lens frame moves in the optical axis direction and abuts on a comparatively large abutment surface crossing an optical axis at right angles to suppress concentration of stress at contact, so that the breakage of a lens is prevented.
On the other hand, another conventional lens barrel has a lens barrel structure shown in an enlarged view of a main part in FIG. 12. This lens barrel 100 has a barrel main body 101, a guide shaft 102 fixed to the barrel main body 101 in parallel with a lens optical axis O, and a lens frame 103 supported by the guide shaft 102. The lens frame 103 is formed into an L-shape, and has a guide portion 103a fitted into the guide shaft 102 and a lens holding portion 103b which holds a lens 104.
In a case where the conventional lens barrel 100 shown in FIG. 12 receives an impact force and the lens frame 103 drops down along the guide shaft 102 in an S0 direction, as shown in a collision state diagram of FIG. 13, either of the guide portion 103a and the lens holding portion 103b collides with an abutment surface 101a or 101b crossing the optical axis O at right angles. Even after the collision, as shown in a repulsive state diagram of FIG. 14, the portion is repulsed from the abutment surface 101a, 101b owing to repulsion to move in an S1 direction.